Wallboard (also known as drywall) has become the dominant material in the production of interior building partitions. In particular, interior building partitions generally comprise a studwall of spaced parallel vertical members (studs) which are used as a support for preformed panels (wallboard) which are attached to the studwall by screws, nails, adhesive or any other conventional attachment system. Obviously, joints exist between adjacent preformed panels. In order to provide a continuous flat surface to the wall, it is necessary to “finish” the joint between adjacent panels. Generally, such “finishing” may include the building up of multiple layers of a mastic material (joint compound) and the blending of this joint compound and paper substrate suitable for wallboard tape utility into the panel surface so as to form the desired flat and contiguous wall surface. In addition, wallboard tape may be used to bring together a plurality of panels forming a corner which may include but is not limited to corner bead.
In order to facilitate this finishing of the joints and/or corners, most manufacturers bevel the longitudinal edges of the wallboard panels so as to allow a build-up of mastic material which will then match the level of the major surface area of the preformed panel. Typically, the buildup of the mastic material in the joint area comprises the application of a first layer of mastic material, the embedding of a wallboard tape (for example a paper tape) in the first layer of mastic material and then the overcoating of the tape with one or more, generally two layers of additional mastic material. This finishing of the joints is a time consuming process, since it is generally necessary to wait 24 hours between each application of a coat of mastic material in order to allow the coat to dry before the application of an overcoat of an additional layer of mastic material. Moreover, it is then necessary generally to sand the joint area so as to produce a finish which will match the major portion of the surface area of the wallboard panels. The “finishing” process thus is both time-consuming and labor-intensive.
Wallboard tape paper is a very challenging paper to make as there is a very narrow window of operation in which to achieve the required high tensile strengths while maintaining other good physical properties such as bonding properties, bonding of joint tape to joint compound, hygroexpansivity, curl, etc. For example, conventional methods of making paper substrates suitable for use as wallboard tape require environments having pHs of less than 7.0 and/or “acidic” conditions. However, a growing number of environmental concerns are forcing paper substrate manufacturers to provide paper making environments having pH's of at least 7.0 and/or “basic” or “alkaline” conditions. The challenge to the next generation of wallboard tape paper substrate production is to program the very specific and stringent levels of physical properties such as CD tensile, MD tensile, internal bond, wet tensile, hygroexpansivity, curl, bonding properties, bond of joint tape to joint compound, etc (which are demanded by wallboard tape paper substrate converters and users) into an alkaline-based paper substrate itself prior to converting and/or use. Such levels of physical properties such as CD tensile, MD tensile, internal bond, wet tensile, hygroexpansivity, curl, bonding properties, bond of joint tape to joint compound, etc, have been achieved by conventional production of paper substrates under acidic conditions. Presently, a paper substrate made within alkaline environments and suitable for wallboard tape converting (e.g. have acceptable physical properties such as CD tensile, MD tensile, internal bond, wet tensile, hygroexpansivity, curl, bonding properties, bond of joint tape to joint compound, etc) has been difficult to achieve, limiting the supply chain of such paper substrates to only those few papermaking sources reserved for production of paper substrates under acidic conditions.
Despite the considerable efforts, there existed a need for a wallboard tape to satisfy the construction industries' requirements for an alkaline wallboard tape having highly sought after physical properties.